Sound-reproducing amplifier



Nov. 19; 1929. N. LALLI SOUND REPRODUCING AMPLIFIER Filed April 22. 1926 2 Sheets-Sheet Nov. 19, 1929. N. LALLI 1,736,606

SOUND REPRQDUCING AMPLIFIER Filed April 22. 1926 2 ShQGtS-SheGt 2 5y uQZZ/vzej W W Patented Nev. 19, 1929 UNITED STATES PATENT OFFICE SOjUND-REPRODUCING AMPLIFIER Application filed April 22, 1926. Serial No. 103,866.

This invention relates primarily to sound reproducing and amplifying devices, and the prmcipal object ofthe invention is to provide a speaker of novel form capable of reas producing sounds in a generally improved manner.

Another object of the invention is to provide a loud speaker which in its novel structural characteristics takes advantage of the superior resonance and acoustic qualities of wood.

Another object of the invention is to provide a loud speaker from which the sounds emanate with substantial uniformity from wall sides. 7

The invention further contemplates the provision of a satisfactory loud speaker at a comparatively low manufacturing cost. in theattached drawings: p Figure 1 is a vertical section through a speaker made in accordance with my invention; 4 2 is a view in perspective of the detached speaker unit;

3 is a front view of the speaker, and Fig. 4; is a fragmentary diagrammatic sectional view illustrating a modification.

. With reference to the drawings, the speaker comprises a casing l whlch in the 30 present instance is circular inform, as shown in Fig. 3, and which is supported upon a suitable base or pedestal 2. The caslng l which preferably is made entirely of Wood consistsof a circular front plate 3 preferably of outwardly dished formation, as shown in Flg.

- 1, and a corresponding back plate 4 having a central opening 5 in which is mounted the reproducing unit 6.

, Extending betweenthe plates 3 and 4 and 4 spacing these plates apart is an annular str1p 7 which completes the casing and which as shown in Fig. 1 ispreferably provided with a series of openings 8 extending around the entire periphery with the exception of that 4 part to which the base 2attaches. lhe casmg 1 is reinforced by means in the present instanceof a pair of'struts9, 9 which extend between the plates 3and 4 adjacent theopeningnfi. i to 1 eumt 6 1s secured to a elreularplate ll which constitutes a closure forthe opening 5 and which may be secured to the back plate 4 by means of screws 22 which pass through apertures 12 in the plate 11 and into" the plate 4. As shown in Fig. 2, this back plate preferably is provided with a plurality of openings 13. a The unit fimaybe of any desired type or' construction, andin the present instance I have shown the speaking unit housed within a cylindrical casing 14:, which latter is Se cured as stated above to the platell. @n the, opposite side this casing has an openingr from which extends in the present instance a small hell-shaped amplifier element 15. p The wires 16 loy means of which the speaker may be connected to the radio set may attach to the unit 6, as shown, andextend through an aperture 17 in the rear plate l. In the present instance, it havh shown means for adjusting the diaphragm of the reproducing nnit after well known manner, this'mea-ns comprising a knob 18 projecting centrally from theplate 11 to which the unit is at-v tached.

Novel and important features of this construction reside first in the fact that by reason of the attachment of the reproducing unit directly to the rear plate fl through the plate 11 whichis securely fixed to said rear plate and the connection of this plate with the front plate 3 throughthe struts 9 which are secured to the front plate near the center thereof, the sound vibrations are transmitted to the comparatively large areas of both of theseplates, with the result that the sounds are amplified to a marked degree. By solid- 13* securing the diaphragm of the reproducing unit to the side plate of the casing, through the casing 14 in which the diaphragm is mounted, the said side plate functions as a soundin board giving marked resonance to the'repro uced tones. It is further found that the amplification covers a comparative- 1y wide tone range. It will further be noted 95 that with this arrangement the sounds emanate from the speaker without any clearly defined directional effect, the sounds emanating in ractically all directions with uni-, form v0 ume.

The design also takes full advantage of the natural resonance and acoustic properties of wood of which the entire casing 1 is made. There is, however, to be no limitation in this respect, since the casing may be made of other materials if this is found desirable. It is further to be noted that the construction is an extremely reasonable one as to vthe cost of manufacture. 4

It will be understood that there may be considerable modification of the general form of the device without departure from the invention.

In Fig. 4, I have illustrated a modification which in all essential respects is similar to the construction illustrated in the other figures, except that in this case the diaphragm of the sound reproducing unit designated by the reference numeral 19 is directly connected with the front plate 3 by means of a rod 21, as clearly illustrated. This gives a direct operative connection between the reproducing unit and the front plate 3.

I claim:

1. A sound reproducing amplifier comprising a casing having front and rear plates of wood co-extensive therewith, the front plate being dished outwardly and the rear plate having a central opening, and an annular strip extending between said plates.

2. A sound reproducing amplifier comprising a casing having front and rear plates of wood co-extensive therewith, the front plate being dished outwardly and the rear plate having a central opening and a perforated annular strip extending between the said plates.

3. A sound reproducing amplifier comprising'a casing having front and rear plates of wood co-extensive therewith, the front plate being dished outwardly and the rear plate having a central opening, an annular strip extending between said plates, and reinforcing means between the front and back plates of said casing.

NICHOLAS LALLI. 

